KR101721816B1 - Damping valve - Google Patents

Abstract

The damping valve includes a valve seat member having a port and a first valve seat, a shaft member mounted on the valve seat member, and a second valve seat mounted on the shaft member and spaced apart from the first valve seat, An auxiliary valve body mounted on the shaft member and spaced apart from the second valve seat, and a second valve seat disposed between the main valve body and the sub valve body, A valve body gap chamber formed on an inner peripheral side of the seat, a restriction passage communicating the port and the valve body with each other to provide resistance to the flow of the passing fluid, and a main valve body member urging the main valve body toward the valve seat member And a sub-valve body pressurizing means for pressing the sub-valve body toward the main valve body. The restriction passage is formed by an annular gap between the main valve body and the shaft member.

Description

DAMPING VALVE

The present invention relates to a damping valve.

The damping valve has a variable damping valve for varying the damping force of the shock absorber interposed between the vehicle body and the axle of the vehicle. As such a damping valve, for example, the applicant of the present application has a valve seat member having an annular valve seat surrounding a port and a port communicating from the cylinder to the reservoir, and a valve seat member which is stacked on the valve seat member, A pilot passage branched from the upstream of the port, an orifice provided in the middle of the pilot passage, a cylindrical spool contacting the opposite side of the annular valve seat of the main valve body, and a spool A pilot valve provided downstream of the pilot passage, and a solenoid for adjusting the valve opening pressure of the pilot valve. The valve housing includes a valve housing movably mounted to form a back pressure chamber on the back side of the main valve body together with the spool, . In this damping valve, a secondary pressure downstream of the orifice in the pilot passage is introduced into the back pressure chamber, and the main valve body is pressurized by this secondary pressure.

In this damping valve, since the pilot valve is provided downstream of the back pressure chamber, when the valve opening pressure of the pilot valve is adjusted by the thrust of the solenoid, the secondary pressure guided to the back pressure chamber is controlled to be the valve opening pressure of the pilot valve.

A secondary pressure acts on the back surface of the main valve body, and the main valve body is pressed toward the annular valve seat. On the front surface of the main valve body, a pressure for separating the main valve body from the annular valve seat acts from upstream of the port. Thereby, when the force for separating the main valve body from the annular valve seat by the pressure on the upstream side of the port exceeds the force for pressing the main valve body to the valve seat by the secondary pressure, the damping valve is opened .

That is, the valve opening pressure of the damping valve can be adjusted by controlling the secondary pressure. When the valve opening pressure of the pilot valve is adjusted by the solenoid, the resistance given by the damping valve to the flow of the hydraulic fluid passing through the flow path can be made variable. Therefore, a desired damping force can be generated in the shock absorber.

In this damping valve, a sub-valve body is laminated on the back surface of the main valve body for opening and closing the main passage so as to increase the variable range of the damping force, and a restrictive passage is provided to pass into the valve body chamber between the main valve body and the sub- Thereby, the main passage is opened in two stages.

The main valve body is mounted on the outer periphery of a shaft provided on the valve seat member and is slidably mounted on the outer periphery of the spacer for fixing the sub valve body. The main valve body is mounted in a floating state with respect to the valve seat member. Thereby, when the main valve body is separated from the annular valve seat, the port can be largely opened. As described above, the main valve body is slidably mounted on the shaft and is guided by the spacer mounted on the shaft, so as to approach or depart from the valve seat member. However, there is a possibility that the inner circumference of the main valve body is caught by the outer periphery of the spacer or abrasion of the outer circumference (stick slip). As a result, the opening / closing response of the port of the main valve body is delayed, which makes it difficult to obtain the desired damping characteristic or may cause vibration.

The main valve body may be constituted by an elastic inner ring portion and an outer ring portion spaced apart from the main valve seat provided on the outer periphery of the inner ring portion. In this case, since the orifice functioning as the limiting passage is provided in the inner ring portion, the fatigue endurance due to the repeated bending of the inner ring portion is disadvantageously deteriorated, and the degree of freedom in designing the bending rigidity is low. Further, since the outer periphery of the inner ring portion is restrained by the outer ring portion, the inner ring portion is structured to be difficult to bend, and the outer ring portion is hard to move with respect to the annular valve seat. As a result, the port opening / closing response of the main valve body is delayed, which may make it difficult to obtain the desired damping characteristic, or may cause vibration.

An object of the present invention is to provide a damping valve capable of obtaining desired damping characteristics without causing vibration.

According to one aspect of the present invention, the damping valve includes a valve seat member having a port and a first valve seat surrounding the port, a shaft member provided on the valve seat member, An annular main valve body mounted on the first valve seat and spaced apart from the first valve seat and having a second valve seat on the opposite side of the valve seat member, A valve body interposed between the main valve body and the sub-valve body and formed on an inner peripheral side of the second valve seat; and a valve body interposed between the valve body and the valve body, A main valve body urging means for urging the main valve body toward the valve seat member side, and a sub valve body urging means for urging the sub valve body toward the main valve body side Respectively. The restriction passage is formed by an annular gap between the main valve body and the shaft member.

1 is a sectional view of an attenuation valve according to an embodiment of the present invention.
2 is a cross-sectional view of a shock absorber to which an damping valve according to an embodiment of the present invention is applied.
3 is a diagram showing the damping characteristics of the shock absorber to which the damping valve according to the embodiment of the present invention is applied.
4 is an enlarged cross-sectional view for explaining the pilot valve of the damping valve according to the embodiment of the present invention.
Fig. 5 is a view showing a time-course of displacement amount of the valve body after the pilot valve is opened. Fig.

Hereinafter, the attenuation valve V according to the embodiment of the present invention will be described with reference to the drawings.

The damping valve V includes a valve seat member 1 having a port 1a and a first valve seat 1b surrounding the port 1a, An assembly mounting shaft 1c as a shaft member provided in the valve seat member 1 and a first valve seat 1b mounted movably in the axial direction with respect to the assembly mounting shaft 1c, A main valve body 2 having an annular main valve body 2 having a first valve seat 2a and a secondary valve seat 2a mounted on the mounting shaft 1c and spaced apart from the second valve seat 2a, A valve inter-cylinder chamber C formed between the valve body 2 and the sub-valve body 3 and formed on the inner peripheral side of the second valve seat 2a and a valve body inter-cylinder chamber C communicating the port 1a and the valve body chamber C, A diaphragm spring 4 as a main valve body urging means for urging the main valve body 2 toward the valve seat member side and a diaphragm spring 4 as a main valve body urging means for urging the sub valve body 3 On the side of the valve body 2 Provided with a back pressure chamber as the valve body portion pressing means for pressing (P).

The damping valve (V) is applied to the shock absorber (D). The shock absorber D generates a damping force by giving a resistance to the working fluid passing through the port 1a mainly when it is expanded or contracted.

2, the shock absorber D to which the damping valve V is applied includes a cylinder 10, a piston 11 slidably inserted in the cylinder 10, A rod seal chamber 13 and a piston seal chamber 14 partitioned by a piston 11 inserted into the cylinder 10 and connected to the piston 11, An intermediate cylinder 16 that covers the outer periphery of the cylinder 10 and forms a discharge passage 15 between the cylinder 10 and the cylinder 10 and a reservoir 17 which covers the outer periphery of the intermediate cylinder 16 and is located between the intermediate cylinder 16, And an outer tube 18 which forms the outer tube 18. In the shock absorber (D), hydraulic oil is filled as working fluid in the rod chamber (13), the piston chamber (14) and the reservoir (17). In addition, the reservoir 17 is filled with gas other than the operating oil. Further, the working fluid can be used in addition to the working fluid, provided that the fluid is capable of generating a damping force.

The shock absorber D is provided with a suction passage 19 for allowing only the flow of the hydraulic fluid from the reservoir 17 to the piston chamber 14 and a suction passage 19 provided for the piston 11 to pass from the piston chamber 14 to the rod chamber 13 And a piston passage (11a) which allows only the flow of the operating fluid directed to the piston. The discharge passage 15 communicates the rod chamber 13 and the reservoir 17. The damping valve V imparts resistance to the flow of the hydraulic fluid passing through the port 1a (see Fig. 1) communicating the reservoir 17 and the discharge passage 15.

When the shock absorber D is compressed, the piston 11 moves to one side (downward in Fig. 2) and the piston chamber 14 is compressed. Then, the operating oil in the piston chamber 14 moves to the rod chamber 13 through the piston passage 11a. In this compression operation, the rod 12 enters the cylinder 10. As a result, in the cylinder 10, the operating fluid of the volume in which the rod 12 enters becomes excessive. Accordingly, the working fluid in excess is extruded from the cylinder 10 and discharged to the reservoir 17 through the discharge passage 15. [ In the shock absorber D, the resistance in the damping valve V is imparted to the flow of the hydraulic fluid passing through the discharge passage 15 to the reservoir 17, so that the pressure in the cylinder 10 rises and the compression side damping force is generated do.

On the other hand, when the extension of the shock absorber D is effected, the piston 11 moves to the other side (upward in Fig. 2) and the rod chamber 13 is compressed. Then, the working oil in the rod chamber 13 moves to the reservoir 17 through the discharge passage 15. [ During this compression operation, the piston 11 moves to the other side and the volume of the piston chamber 14 is enlarged. The working fluid of this enlarged portion is supplied from the reservoir 17 through the suction passage 19 to the piston chamber 14. In the shock absorber D, the resistance in the damping valve V is given to the flow of the hydraulic fluid passing through the discharge passage 15 to the reservoir 17, so that the pressure in the rod chamber 13 rises and the damping force on the extension side Occurs.

As described above, when the expansion / contraction operation is performed, the shock absorber D discharges the working oil from the inside of the cylinder 10 through the discharge passage 15 to the reservoir 17, and the operating oil is supplied to the piston chamber 14, the rod chamber 13 ), And the reservoir 17 in a one-way flow. In the shock absorber (D), damping forces on both sides of compression can be generated by a single damping valve (V).

Next, each part of the damping valve V will be described in detail.

The damping valve V has a valve seat member 1 fitted to a sleeve 16a provided at an opening of the intermediate cylinder 16 and a valve seat member 1 fitted to the outer periphery of an assembly mounting shaft 1c provided on the valve seat member 1. [ An annular main valve body 2 mounted floating on the valve seat member 1 and spaced apart from and seated on the first valve seat 1b and an annular portion 2c mounted on the outer periphery of an assembly mounting shaft 1c provided on the valve seat member 1. [ A valve body 3 and a valve body interspace C formed between the main valve body 2 and the sub-valve body 3 and a restrictor passage (not shown) for communicating the port 1a and the valve body chamber C 5 and a diaphragm spring 4 for urging the main valve body 2 toward the valve seat member side. In addition, the damping valve V includes a valve housing 20 formed hollow and connected to the assembly mounting shaft 1c of the valve seat member 1, and a cylindrical pilot valve A pilot valve body 22 slidably inserted in the pilot valve seat member 21 and a solenoid Sol for imparting thrust to the pilot valve body 22. The solenoid Sol A pilot passage 23 is formed in the valve seat member 1 and the valve housing 20 to guide the pressure in the back pressure chamber P by reducing the pressure on the upstream side of the port 1a.

1, the valve seat member 1 includes a base portion 1d having a large diameter fitted in the sleeve 16a and a base portion 1d projecting from the base portion 1d in the axial direction A hollow portion 1e formed so as to penetrate the base portion 1d and the mounting mounting shaft 1c in the axial direction and forming a part of the pilot passage 23; A plurality of ports 1a extending from the one end (left end in FIG. 1) to the other end (right end in FIG. 1) of the base 1d and a plurality of ports 1a penetrating from the base 1d And an annular first valve seat 1b provided at an end (the right end in Fig. 1) and formed on the outer peripheral side of the outlet of the port 1a.

The port 1a passes through the base 1d as described above. The opening of the port 1a on the side of the one end (left end in Fig. 1) of the base 1d communicates with the rod chamber 13 through the discharge passage 15 formed by the intermediate cylinder 16. The opening of the port 1a on the side of the other end (right end in Fig. 1) of the base 1d communicates with the reservoir 17. That is, in the shock absorber D, the hydraulic oil is discharged from the rod chamber 13 through the discharge passage 15 and the port 1a to the reservoir 17 during the expansion and contraction. At this time, the upstream of the port 1a becomes the rod chamber 13. The opening on the side of the one end (left end in FIG. 1) of the hollow portion 1e also communicates with the rod chamber 13 through the discharge passage 15 like the port 1a.

In the valve seat member 1, a small diameter portion 1g formed to have a small diameter at one end side (left side in Fig. 1) of the base portion 1d is fitted in the sleeve 16a. A seal ring 24 is mounted on the outer periphery of the small diameter portion 1g to seal the sleeve 16a. Therefore, the discharge passage 15 does not communicate with the reservoir 17 through the outer periphery of the base 1d.

A main valve body 2 that is seated on the first valve seat 1b and opens and closes the port 1a is stacked on the other end (right end in Fig. 1) of the base portion 1d of the valve seat member 1 have. The main valve body 2 is annular and has an annular second valve seat 2a protruding from the outer periphery of the valve seat member 1 and a second valve seat 2b opposite to the valve seat member 1, 2b provided on the inner circumferential side of the annular projecting portion 2a. Specifically, the main valve body 2 is mounted on the outer periphery of the assembly mounting shaft 1c of the valve seat member 1, and is installed on the outer periphery of the annular spacer 25 so as to be movable in the axial direction. The inner diameter of the main valve body 2 is formed to be larger than the outer diameter of the spacer 25. An annular gap is formed between the main valve body (2) and the spacer (25). The restriction passage 5 is formed by the annular gap.

If it is not necessary to provide the spacer 25, the restriction passage 5 may be formed by forming an annular gap between the mounting mounting shaft 1c and the main valve body 2. The spacer 25 is mounted on the outer periphery of the mounting mounting shaft 1c to fix the sub valve body 3 on the outer periphery of the mounting mounting shaft 1c. In the present embodiment, the spacers 25 are integrated with the assembly mounting shaft 1c to form a shaft member together with the mounting mounting shaft 1c. The thickness of the spacer 25 in the axial direction is larger than the thickness in the axial direction of the inner circumference of the main valve body 2. [ Thereby, the main valve body 2 can move in the axial direction (the left-right direction in Fig. 1).

As described above, the main valve body 2 is assembled and mounted so as to be movable in the axial direction with respect to the valve seat member 1. Thereby, the main valve body 2 can be seated on the first valve seat 1b by making a distance to the valve seat member 1. [ The main valve body 2 opens the port 1a in a state of being separated from the first valve seat 1b and closes the outlet end of the port 1a in a state of being seated on the first valve seat 1b .

On the back side of the main valve body (2), the sub valve body (3) is laminated. A diaphragm spring 4 for pressing the main valve body 2 toward the first valve seat 1b is interposed between the sub valve body 3 and the spacer 25. The sub valve body (3) is an annular laminated leaf valve. The subsidiary valve body 3 is assembled and mounted on the inner peripheral mounting mounting shaft 1c together with the disc spring 4. [ The auxiliary valve body 3 is fitted and held by the valve housing 20 which is screwed to the spacer 25 and the mounting mounting shaft 1c.

The disc spring (4) has three arm portions functioning as springs on the outer periphery of the ring portion. The annular portion is fitted and held by the spacer 25 and the valve housing 20. The free end portion of the arm portion is fitted to the inner circumference of the annular protruding portion 2b provided at the end of the main valve body 2 opposite to the valve seat member 1. The diaphragm spring 4 not only presses the main valve body 2 with the first valve seat 1b but also positions the main valve body 2 in the radial direction with respect to the valve seat member 1. [ Thereby, the main valve body 2 does not move freely in the radial direction with respect to the valve seat member 1. [

The projecting portion 2b of the main valve body 2 may not be an annular shape as long as the main valve body 2 can be positioned radially by the diaphragm spring 4. [ For example, instead of the annular protruding portion 2b, a plurality of protruding portions opposed to the outer periphery of the disc spring 4 may be arranged in the peripheral direction so that the positioning of the main valve body 2 in the radial direction may be possible . In addition to the diaphragm spring 4, the main valve body pressurizing means has a plurality of resilient arm portions extending radially from the annular portion as a ring portion fixed by the spacer 25, The main valve body 2 may be positioned and pressurized. It is also possible to use an elastic body such as a spring washer or rubber as the main valve body pressing means.

On the other hand, the sub-valve body 3 can be seated on the second valve seat 2a of the main valve body 2 by being permitted to warp on the outer peripheral side. The inner periphery of the sub-valve body 3 is stacked on the spacer 25, and the outer periphery thereof is seated on the second valve seat 2a. There is a space between the sub-valve body (3) and the main valve body (2). This space is the valve inter-body chamber (C).

The sub valve body 3 is a laminated leaf valve in which a plurality of annular plates are stacked, but the number of annular plates is arbitrary. Further, an orifice 3a formed in a notch shape is provided on the outer periphery of the annular plate seated on the second valve seat 2a. The orifice 3a may be formed by notching the second valve seat 2a of the main valve body 2 but not the sub valve body 3 and the first valve seat 1b of the valve seat member 1, Or the main valve body 2 in contact with the second valve seat 2a.

The valve intercondition chamber C is communicated with the port 1a by the restriction passage 5 between the main valve body 2 and the spacer 25. The diaphragm spring (4) permits the passage of the working oil through the space between the arm portion and the arm portion. Thereby, the valve body chamber C is not closed. Further, the diaphragm spring 4 is not limited to the above-described structure as long as it does not block the valve inter-cylinder chamber C. In the case where the leaf spring 4 is constituted by a ring portion and a plurality of arm portions, the number of arm portions can be set arbitrarily. When the main valve body 2 is positioned by the diaphragm spring 4, it is preferable that three or more arm portions are provided. The restrictor passage (5) gives resistance to the flow of the operating hydraulic oil passing therethrough. When the operating fluid that has passed through the port 1a passes through the restrictor passage 5 and moves to the valve inter-body chamber C of the main valve body 2, the valve seat member 1 ) And the pressure in the valve body chamber (C) on the back side.

The hydraulic fluid that has passed through the port 1a flows through the restrictor passage 5 and the valve inter-cylinder chamber C until the sub-valve body 3 is separated from the second valve seat 2a of the valve body 2, And the orifice (3a) to the reservoir (17). At this time, the port 1a is in the closed state.

When the sub valve body 3 is bent from the second valve seat 2a by the pressure acting on the valve inter-cylinder chamber C through the restrictive passage 5, the second valve seat 2 of the main valve body 2 2a and the sub-valve body 3 is formed. The hydraulic oil that has passed through the port 1a and the restrictor passage 5 escapes between the sub valve body 3 and the main valve body 2 and moves to the reservoir 17. [ That is, even if the main valve body 2 is seated on the first valve seat 1b, when the sub valve body 3 is bent and separated from the second valve seat 2a, the port 1a is opened and the reservoir 17 .

When the main valve body 2 is pushed up by the pressure received from the port 1a together with the secondary valve body 3 being deflected, the entire main valve body 2 is separated from the valve seat member 1, And is separated from the valve seat 1b. In this case, the operating oil that has passed through the port 1a is discharged to the reservoir 17 through the annular gap generated between the main valve body 2 and the first valve seat 1b.

A distance piece 26, an annular leaf spring 27, and a distance piece 28 are stacked in order on the other end side (right side in FIG. 1) of the sub valve body 3 and assembled to the assembly mounting shaft 1c Respectively. A valve housing 20 is screwed to the distal end (right end in Fig. 1) of the assembly mounting shaft 1c. Thereby, the spacer 25, the valve member 3, the distance piece 26, the leaf spring 27, and the distance piece 28 assembled to the assembly mounting shaft 1c are engaged with the valve seat member 1 And the valve housing 20, and is fixed. The main valve body 2 mounted on the outer periphery of the spacer 25 is provided in a floating state on the outer periphery of the spacer 25 and is movable in the axial direction. The inner periphery of the leaf spring 27 is fixed to the assembly mounting shaft 1c, and the outer periphery thereof is a free end.

1, the valve housing 20 has a small-diameter tubular portion 20a formed in one end side (left side in FIG. 1) and having a small outer diameter, and a small-diameter tubular portion 20b formed on the other end side A large diameter tubular portion 20b formed in the large diameter tubular portion 20b and having a large outer diameter as compared with the small diameter tubular portion 20a and a pressure introducing side hole 20d communicating with the inner circumference of the large diameter tubular portion 20b, And a pressure introducing longitudinal hole 20e which opens at one end (left end in FIG. 1) and communicates with the pressure introducing transverse hole 20d. The valve housing 20 is provided with an assembly mounting shaft 1c of a valve seat member 1 inserted and screwed into a screw hole portion 20f formed inside the small diameter cylindrical portion 20a so that the valve seat member 1 . Further, the pressure introducing transverse hole 20d and the pressure introducing longitudinal hole 20e may be formed as a single hole that is opened at an angle, for example.

The annular projecting portion 20g is provided on the inner peripheral side of the other end (the right end in Fig. 1) of the large-diameter cylindrical portion 20b, and a plurality of tools A hole 20h is formed. The valve housing 20 is easily screwed to the assembly mounting shaft 1c by inserting and rotating the tool into the tool hole 20h.

A tubular spool 30 is slidably mounted on the outer periphery of the large-diameter tubular portion 20b of the valve housing 20. As shown in Fig. The spool 30 is formed in a cylindrical shape. The spool 30 has a flange 30a projecting from the one end (the left end in Fig. 1) to the inner circumference and an annular projection 30b similarly projecting from the one end in the axial direction. The spool 30 is movable in the axial direction (the left-right direction in Fig. 1) with respect to the valve housing 20. Fig.

The outer periphery of the leaf spring 27 is in contact with the inner end (the right end in Fig. 1) of the flange 30a. The spool 30 is urged toward the sub valve body 3 (left side in Fig. 1) by the leaf spring 27 and the annular protrusion 30b is in contact with the side surface of the sub valve body 3 .

The spool 30 defines a back pressure chamber P between the plate spring 27 on the inner circumferential side and the valve housing 20. The back pressure chamber P is communicated with the valve housing 20 through the pressure introducing longitudinal hole 20e and the pressure introducing transverse hole 20d.

The valve housing 20 communicates with the hollow portion 1e of the valve seat member 1 and communicates with the rod chamber 13 upstream of the port 1a through the orifice 1f. Therefore, the hydraulic fluid discharged from the rod chamber 13 is guided to the back pressure chamber P through the orifice 1f. That is, the pressure upstream of the port 1a is reduced by the orifice 1f to be introduced into the back pressure chamber P.

The auxiliary valve body 3 is provided on the back surface of the main valve body 3 by the internal pressure of the back pressure chamber P in addition to the pressing force by the leaf spring 27 for pressing the spool 30, A pressing force is applied which urges the light emitting diode 2 toward the light emitting diode. That is, when the shock absorber D expands and contracts, the pressure in the rod chamber 13 acts on the main valve body 2 from the front side through the port 1a, and the pressing force of the diaphragm spring 4 The internal pressure of the back pressure chamber P and the urging force of the leaf spring 27 act through the sub-valve body 3.

Sectional area of the flange 30a on the other end side (the right side in Fig. 1) of the spool 30 multiplied by the pressure of the back pressure chamber P is applied to the main valve body 2 As shown in Fig. A force obtained by multiplying the inner diameter cross-sectional area of the second valve seat 2a by the pressure of the valve body chamber C acts on the sub-valve body 3 in a direction away from the main valve body 2. The ratio of the pressure in the back pressure chamber P to the valve opening pressure of the sub valve body 3 is set such that the inner diameter cross sectional area of the flange 30a on the other end side Sectional area of the two-valve seat 2a. It is also possible to form a hole in the leaf spring 27 so that the pressure in the back pressure chamber P directly acts on the valve body 3.

The pressure in the valve inter-cylinder chamber C is increased by the pressure in the rod chamber 13 and the force for bending the outer periphery of the sub-valve body 3 in the other direction (rightward in Fig. 1) The valve body 3 is bent so as to be spaced from the second valve seat 2a. A gap is formed between the sub-valve body 3 and the main valve body 2, so that the port 1a is opened. In the present embodiment, the inner diameter of the second valve seat 2a is larger than the inner diameter of the first valve seat 1b. That is, the hydraulic pressure area in which the main valve body 2 receives the pressure on the port 1a side and the hydraulic pressure area on which the main valve body 2 receives the pressure on the valve body chamber C side have a difference. Thereby, when the differential pressure generated by the restriction passage 5 does not reach the valve opening pressure for separating the main valve body 2 from the first valve seat 1b, the main valve body 2 is closed, 1b.

On the other hand, when the sub-valve body 3 is in the bent-valve open state and the differential pressure generated by the restriction passage 5 reaches the valve opening pressure for separating the main valve body 2 from the first valve seat 1b, The main valve body 2 is also separated from the first valve seat 1b to open the port 1a. The pressure increasing ratio in the sub valve body 3 is set to be smaller than the pressure increasing ratio in the main valve body 2 which is the ratio of the valve opening pressure of the main valve body 2 to the pressure in the valve body chamber C . That is, the pressure in the rod chamber 13 when the valve element 3 is opened is lower than the pressure in the rod chamber 13 when the main valve element 2 is opened. That is, the valve opening pressure of the sub valve body 3 is set to be lower than the valve opening pressure of the main valve body 2.

A cylindrical pilot valve seat member 21 is accommodated in the valve housing 20 and on the other end side (right side in FIG. 1) of the screw hole portion 20f. The pilot valve seat member 21 includes a bottomed cylindrical valve receiving cylinder 21a and a flange portion 21b protruding from the outer periphery of the other end (right end in FIG. 1) of the valve receiving cylinder 21a A through hole 21c which opens radially from the side surface of the valve receiving cylinder 21a and communicates with the inside of the valve receiving cylinder 21a and an opposite end portion An annular pilot valve seat 21d protruded and an annular valve urging portion 21e provided on the outer periphery of the flange portion 21b so as to be thicker than the flange portion 21b.

On the outer periphery of the annular protruding portion 20g of the valve housing 20, a fail valve body 31 formed of an annular laminated leaf valve is mounted. The fail valve body 31 is fitted and held by the other end portion (right end in FIG. 1) of the large-diameter tubular portion 20b of the valve housing 20 and the valve urging portion 21e of the pilot valve seat member 21 . The inner circumference of the fail valve body 31 is fixed and the outer circumference is bent.

In the valve receiving cylinder 21a of the pilot valve seat member 21, the pilot valve body 22 is slidably inserted in the axial direction. The pilot valve body 22 has a small diameter portion 22a on the pilot valve seat member 21 side (the left end side in FIG. 1) slidably inserted in the valve accommodating cylinder 21a, An annular concave portion 22c formed between the small diameter portion 22a and the large diameter portion 22b and a large diameter portion 22b formed on the opposite side of the pilot valve seat member 21 A communication passage 22e penetrating from the front end to the rear end portion of the pilot valve body 22 and an orifice 22c provided in the middle of the communication passage 22e, And an annular projection 22g provided on the outer periphery of an end portion of the spring shoe portion 22d opposite to the pilot valve seat member 21.

The concave portion 22c of the pilot valve element 22 is always opposed to the through hole 21c when the pilot valve element 22 moves in the axial direction within a range allowed for the pilot valve seat member 21 . Therefore, the pilot valve body 22 does not block the through hole 21c.

The pilot valve body 22 has a large diameter on the opposite side of the pilot valve seat member 21 with the recess 22c as a boundary. The pilot valve element 22 has an annular seating portion 22h opposed to the pilot valve seat 21d at one end (left end in FIG. 1) of the large diameter portion 22b. The pilot valve body 22 moves in the axial direction with respect to the pilot valve seat member 21 so that the seating portion 22h is spaced apart from the pilot valve seat 21d. Thus, the pilot valve body 22 and the pilot valve seat member 21 constitute the pilot valve PV. The pilot valve PV is closed when the seating portion 22h is seated on the pilot valve seat 21d.

A disc 32 having a hole to be fitted to the inner circumference of the annular projection 22g is laminated on an end of the spring shoe portion 22d opposite to the side of the pilot valve seat member 21. [ The communication path 22e communicates with the back side (the right end side in Fig. 1) of the disc 32 having the hole opened through the hole of the hole 32 having the hole. A coil spring 33 for pressing the pilot valve element 22 to the opposite side of the pilot valve seat member 21 is interposed between the spring shoe portion 22d and the flange portion 21b. The pilot valve body 22 is constantly urged by the coil spring 33 to the opposite side of the pilot valve seat member 21. [ The pilot valve PV is in a valve-opened state when a thrust opposed to the coil spring 33 by a solenoid (Sol) described later does not act. Although the coil spring 33 is used to press the pilot valve element 22 in a direction separating it from the pilot valve seat member 21, an elastic body capable of exerting a pressing force other than the coil spring 33 can be used.

When the pilot valve element 22 is inserted into the valve receiving cylinder 21a of the pilot valve seat member 21, the space K is defined on the tip end side from the through hole 21c in the valve receiving cylinder 21a. The space K is communicated with the outside of the pilot valve PV through the communication passage 22e provided in the pilot valve body 22 and the orifice 22f. Thus, when the pilot valve element 22 moves in the axial direction (left-right direction in Fig. 1) with respect to the pilot valve seat member 21, the space K functions as a dash port. Therefore, sudden movement of the pilot valve body 22 can be suppressed, and vibration movement of the pilot valve body 22 can be suppressed.

A fail valve seat member 34 that is stacked on the other side of the valve housing 20 (the right side in FIG. 1) is provided on the outer periphery of the pilot valve body 22. The fail-valve seat member 34 is formed in an annular shape and has a socket portion 34a fitted to the outer periphery of the large-diameter tubular portion 20b of the valve housing 20 and a socket portion 34a formed on the valve housing 20 side A fail valve seat 34c provided on the outer periphery of the annular window 34b, an annular recess 34d provided on the inner periphery of the annular window 34b, A plurality of passages 34e which are formed over the annular concave portion 34d and communicate with the annular window 34b and a plurality of annular projections 34c which are provided so as to protrude from the inner periphery of the end portion on the opposite side of the valve housing 20 A plurality of notches 34g provided at the end of the valve housing 20 opposite the valve housing 20 (right side in FIG. 1) and a through hole 34h penetrating the socket portion 34a in the radial direction do.

The inner diameter of the other portion of the fail valve seat member 34 except for the flange 34f is of a size that does not disturb the movement of the pilot valve element 22. [ When the pilot valve body 22 is pressed in the other direction (right direction in FIG. 1) by the coil spring 33 while the pilot valve body 22 is not receiving the thrust from the solenoid (Sol) The outer periphery of the annular projection 22g of the body 22 contacts the flange 34f. At this time, the pilot valve body 22 can not move further to the opposite side (right side in Fig. 1) of the valve housing 20. Therefore, the opening end of the fail valve seat member 34 on the opposite side (right side in Fig. 1) of the valve housing 20 is closed by the pilot valve body 22.

When the fail valve seat member 34 is stacked on the valve housing 20, the valve pressing portion 21e of the pilot valve seat member 21 is fitted into the annular recess 34d. Thereby, the valve-pressing portion 21e is fitted and fixed together with the fail-valve body 31 by the fail-valve seat member 34 and the valve housing 20. [ The valve housing 21 of the pilot valve seat member 21 is received in the valve housing 20 and the outer periphery of the valve pressing portion 21e is fitted to the annular recess 34d of the fail- And is fitted. Thereby, the pilot valve seat member 21 is positioned in the radial direction with respect to the fail valve seat member 34.

The fail valve body 31 is seated on the fail valve seat 34c of the fail valve seat member 34 to close the annular window 34b. The fail valve body 31 is spaced apart from the fail valve seat 34c to open the annular window 34b by the action of pressure from the annular window 34b side. Thereby, the passage 34e communicates with the reservoir 17 through the through hole 34h. As described above, the fail valve F is constituted by the fail valve body 31 and the fail valve sheet member 34. The passage 34e is formed by a groove formed on the valve housing side of the fail-valve seat member 34. [ Therefore, the passage 34e is very easy to process. It is also possible to form the passage 34e by the hole instead of the groove.

As described above, the damping valve V communicates the rod chamber 13 and the reservoir 17 with the port 1a. The damping valve V opens and closes the port 1a with the main valve body 2 and the sub valve body 3. In addition to the route through the port 1a, the rod seal chamber 13 and the reservoir 17 are formed in the hollow portion 1e of the valve seat member 1, in the valve housing 20, Which is made up of the through hole 21c of the pilot valve seat member 21, the recess 22c of the pilot valve member 22, the fail valve seat member 34 and the notch 34g in the pilot valve seat member 21 23).

The pilot passage 23 communicates with the back pressure chamber P through the pressure introducing transverse hole 20d of the valve housing 20 and the pressure introducing longitudinal hole 20e. In the back pressure chamber P, the pressure upstream of the port 1a is reduced by the orifice 1f provided in the middle of the pilot passage 23 and introduced. The pilot passage 23 is opened and closed by the pilot valve PV. The pilot passage 23 can control the pressure in the back pressure chamber P by adjusting the opening degree of the pilot valve PV. The pilot passage 23 has a solenoid (Sol) that applies thrust to the pilot valve body 22 to adjust the opening degree of the pilot valve (PV).

When the pilot valve body 22 is pressed by the coil spring 33, the outer periphery of the annular projection 22g of the pilot valve body 22 comes into contact with the flange 34f and the cutout 34g and the fail- The communication in the member 34 is broken. In this state, when the pressure in the pilot passage 23 becomes high and reaches the valve opening pressure of the fail valve body 31, the fail valve body 31 is separated from the fail valve seat 34c. Thereby, the pilot passage 23 communicates with the reservoir 17 through the passage 34e, the annular concave portion 34d, and the through hole 34h.

The solenoid (Sol) is accommodated in a bottomed tubular case (35) which is screwed on the outer periphery of a sleeve (18a) mounted on the opening of the outer tube (18). The solenoid (Sol) includes an annular solenoid bobbin (39) wound around a winding (38) and fixed to the bottom of the case (35), and a solenoid bobbin The first fixed iron core 40 is fixed to the inner circumference of the solenoid bobbin 39 by a second fixed iron core 41 which is fitted in the inner circumference of the solenoid bobbin 39, A non-magnetic filler ring 42 which forms a gap between the second fixed iron cores 41, a tubular movable iron core 43 which is disposed on the inner circumferential side of the first fixed iron core 40, And a shaft 44 fixed to the inner periphery of the shaft.

The case 35 has a barrel portion 35a and a bottom portion 35b fixed by caulking the opening end portion of the barrel portion 35a. The bobbin holder 36 is fixed to the inner periphery of the cylindrical portion 35a when the opening end of the cylindrical portion 35a is caulked. The bobbin holder (36) holds the solenoid bobbin (39). The solenoid bobbin 39 is mounted to the case 35 through the bobbin holder 36.

When the case 35 is screwed to the sleeve 18a, the outer peripheral flange 41a of the second fixed core 41 is fitted between the case 35 and the sleeve 18a. Thereby, the pillar ring 42 and the first fixed core 40 are fixed in the case 35 by the second fixed core 41. [

The movable iron core 43 is formed in a cylindrical shape and a shaft 44 extending in the axial direction (left and right direction in FIG. 1) from both ends of the movable iron core 43 is mounted on the inner periphery thereof. The shaft 44 has an annular bush 45 provided at the bottom of the first fixed core 40 and an annular guide 46 fitted to the inner periphery of the second fixed core 41 And is held by the bush 47 in the axial direction. The axial movement of the shaft 44 is guided by the bushes 45 and 47.

When the second fixed iron core 41 is fixed to the case 35, the guide 46 fitted to the inner periphery of the second fixed iron core 41 contacts the fail valve seat member 34, 34, the pilot valve seat member 21, the valve housing 20 and the valve seat member 1 are fixed to the shock absorber D. [ At this time, the cutout 34g is provided so that the pilot passage 23 is not blocked even if the guide 46 comes into contact with the other end (right end in Fig. 1) of the fail-valve seat member 34. [

One end (left end in FIG. 1) of the shaft 44 is in contact with the disk 32 having a hole that is fitted in the other end (the right end in FIG. 1) of the pilot valve body 22. The urging force of the coil spring 33 also acts on the shaft 44 through the pilot valve element 22. The coil spring 33 not only presses the pilot valve body 22 but also presses the shaft 44 as a part of the solenoid (Sol).

The second fixed core 41 has a cylindrical sleeve 41b fitted in the inner periphery of the sleeve 18a. Thereby, the respective members constituting the solenoid (Sol) are positioned in the radial direction with respect to the sleeve (18a). The cutout is provided on the outer periphery of the fail-valve seat member 34 so that the gap between the sleeve 41b and the fail-valve seat member 34 is not blocked. By this cutting, the flow passage area of the pilot passage 23 is sufficiently secured. Further, the dimension of the axial length of the sleeve 41b is set so as not to interfere with the spool 30.

In the guide 46, a hole 46a penetrating in the axial direction is formed. Thereby, a pressure difference does not occur at one end side (left side in FIG. 1) and the other end side (right side in FIG. 1) of the guide 46. The movable core 43 also has a hole 43a penetrating in the axial direction. Thereby, a pressure difference does not occur at one end side (left side in FIG. 1) and the other end side (right side in FIG. 1) of the movable core 43. Therefore, smooth movement of the movable iron core 43 is not hindered.

As described above, the solenoid (Sol) is formed such that the magnetic path passes through the first fixed core 40, the movable core 43, and the second fixed core 41. When the winding wire 38 is excited, the movable iron core 43 disposed in the vicinity of the first fixed iron core 40 is attracted to the second fixed iron core 41 side. As a result, a thrust directed toward one end side (left side in Fig. 1) acts on the movable iron core 43. [

The shaft 44, which moves integrally with the movable iron core 43, is in contact with the pilot valve body 22 of the pilot valve PV as shown in Fig. Therefore, the thrust of the solenoid (Sol) is transmitted to the pilot valve body (22). When the solenoid (Sol) is energized, thrust in the direction toward one end side (left side in Fig. 1) can be given to the pilot valve element (22) through the movable core (43). When the solenoid (Sol) is not energized, the pilot valve body (22) is pressed against the coil spring (33) and separated from the pilot valve seat (21d). As a result, the pilot valve (PV) is opened to the maximum, and the pilot valve body (22) is seated on the flange (34f) of the fail valve seat member (34). Therefore, the pilot passage 23 is closed to make the fail valve F effective.

Further, the thrust applied to the pilot valve element 22 can be adjusted by adjusting the amount of electric current flowing to the coil 38 of the solenoid (Sol). Thereby, the valve opening pressure of the pilot valve (PV) can be controlled. More specifically, when a current is supplied to the solenoid (Sol) to apply a thrust to the pilot valve body (22), the pilot valve body (22) of the pilot valve (PV) And is pressed against the pilot valve seat 21d. The pressure on the upstream side of the pilot passage 23 acts on the pilot valve body 22 so that the force that separates the pilot valve body 22 from the pilot valve seat 21d and the pressing force of the coil spring 33 The pilot valve PV is opened to open the pilot passage 23. In this case, as shown in Fig. That is, when the pressure on the upstream side of the pilot passage 23 reaches the valve opening pressure, the pilot valve PV is opened to open the pilot passage 23.

Thus, by adjusting the thrust of the solenoid (Sol) by the amount of the current supplied to the solenoid (Sol), the magnitude of the valve opening pressure of the pilot valve (PV) can be adjusted. When the pilot valve (PV) is opened, the pressure on the upstream side of the pilot valve (PV) in the pilot passage (23) becomes equal to the valve opening pressure of the pilot valve (PV). The pressure of the back pressure chamber P into which the pressure upstream of the pilot valve PV of the pilot passage 23 is introduced is also controlled to be the valve opening pressure of the pilot valve PV.

Next, the operation of the damping valve V will be described.

The hydraulic oil in the discharge passage 15 is discharged to the reservoir 17 via the damping valve V when the buffer D is expanded and contracted and discharged from the rod chamber 13 to the discharge passage 15. [ At this time, in the damping valve (V), the pressure upstream of the port (1a) and the pilot passage (23) becomes high. When the damping valve V normally operates, the current is supplied to the solenoid (Sol) to regulate the valve opening pressure of the pilot valve (PV), the orifice (1f) in the pilot passage (23) (PV) is guided to the back pressure chamber (P).

The internal pressure of the back pressure chamber P is controlled to be the valve opening pressure of the pilot valve (PV). When the valve opening pressure of the pilot valve (PV) is adjusted by the solenoid (Sol), the pressure acting on the back surface of the sub valve body (3) can be adjusted. Thereby, the sub valve body 3 can control the valve opening pressure for opening the port 1a.

Specifically, the pressure in the valve inter-cylinder chamber C is increased by the pressure in the rod chamber 13, and the force for bending the outer periphery of the sub-valve body 3 in the opening direction (the right direction in Fig. 1) When the internal pressure of the chamber P and the pressing force by the plate spring 27 are exceeded, the sub valve body 3 is bent and separated from the second valve seat 2a. Thereby, a gap is formed between the sub-valve body 3 and the main valve body 2, and the port 1a is opened. Therefore, by adjusting the magnitude of the pressure in the back pressure chamber P, it is possible to adjust the magnitude of the pressure in the valve inter-body chamber C, which is the pressure for separating the sub-valve body 3 from the second valve seat 2a. That is, the valve opening pressure of the sub-valve body 3 can be controlled by the amount of current given to the solenoid (Sol).

Therefore, the damping characteristic (characteristic of the damping force with respect to the piston speed) of the damping valve V is as shown in Fig. That is, until the valve body 3 is opened, the hydraulic oil passes through the sliding gap of the damping valve V and the orifice 3a, so that the characteristic having a constant slope (the state shown by line X in FIG. 3) . When the sub valve body 3 is separated from the second valve seat 2a to open the port 1a, the inclination becomes small (a state indicated by a line Y in Fig. 3). Therefore, the damping coefficient becomes small.

As described above, since the pressure increasing ratio in the sub-valve body 3 is made smaller than the pressure increasing ratio in the main valve body 2, the valve opening pressure of the sub-valve body 3 is controlled by the main valve body 2). ≪ / RTI > The main valve body 2 is brought into contact with the first valve seat 1b when the differential pressure generated by the restrictive passage 5 does not reach the valve opening pressure which separates the main valve body 2 from the first valve seat 1b, .

On the other hand, the piston speed of the shock absorber D is increased in the state in which the sub valve body 3 is bent and the valve is opened so that the differential pressure generated by the restrictor passage 5 is transmitted to the first valve seat 1b, The main valve body 2 is separated from the first valve seat 1b to open the port 1a against the urging force of the diaphragm spring 4. Then, Then, when only the sub-valve body 3 is in a valve-opened state and the port 1a is communicated with the reservoir 17 only through the restrictor passage 5, the main valve body 2 is closed by the first valve seat 1b So that the port 1a directly communicates with the reservoir 17 without passing through the restrictive passage 5, so that the flow path area becomes large. Therefore, the damping characteristic of the damping valve V becomes smaller than the case where only the valve element 3 is in the valve-opened state (state indicated by line Z in Fig. 3). Therefore, the damping coefficient is further reduced.

When the valve opening pressure of the pilot valve (PV) is increased or decreased by adjusting the amount of passage to the solenoid (Sol), the damping valve (V Can be changed. It is also possible to make the pressure increasing ratio in the sub-valve body 3 smaller than the pressure increasing ratio in the main valve body 2. [ By doing so, the valve opening pressure of the sub-valve body 3 becomes smaller than the valve opening pressure of the main valve body 2, and the port 1a is relieved in two steps. Therefore, in the damping valve V, the damping force in the full soft state in which the valve opening pressure of the pilot valve PV is minimum can be made smaller than that in the conventional damping valve. Therefore, the variable range of the damping force can be increased.

Therefore, according to the damping valve V, a soft damping force can be outputted when the piston speed of the shock absorber D is in the low speed region, and the damping force is not increased. Further, the upper limit of the hard damping force required when the piston speed of the shock absorber D is in the high speed region can be increased, and the damping force is not caused to be insufficient. Therefore, when the damping valve V is applied to the shock absorber D, the variable range of the damping force can be increased and the ride comfort of the vehicle can be improved.

According to the above-described embodiment, the following operational effects are exhibited.

In the damping valve V, the radial position of the main valve body 2 is determined by the diaphragm spring 4, and the annular gap between the main valve body 2 and the mounting mounting shaft 1c restricts the passage 5). Thereby, the main valve body 2 can move in the axial direction with respect to the valve seat member 1, while maintaining the restrictive passage 5. Therefore, the inner circumference of the main valve body 2 is not worn by being caught by the outer periphery of the shaft member.

It is sufficient that the diaphragm spring 4 does not function as the main valve body 2 but exerts a pressing and positioning function of the main valve body 2. [ Therefore, it is possible to design so as not to disturb the movement of the main valve body 2 in the axial direction. Therefore, with the damping valve V, desired damping characteristics can be obtained without causing vibration. Further, since the diaphragm spring 4 does not need to be provided with the limiting passage 5, the degree of freedom in designing the bending rigidity of the diaphragm spring 4 is increased, and fatigue endurance due to repetitive bending can be secured easily.

Specifically, when the main valve body pressurizing means is formed by the diaphragm spring 4, when the outer periphery of the diaphragm spring 4 is fitted at a distance to the protruding portion 2b of the main valve body 2 , The outer periphery of the diaphragm spring (4) is not restrained by the main valve body (2). Therefore, the bow of the diaphragm spring 4 is not hindered, and the movement of the main valve body 2 in the axial direction is not hindered. The diaphragm spring 4 does not need to be provided with a restrictive passage. As a result, like the diaphragm spring 4 of the present embodiment, it can be formed by a plurality of arm portions functioning as an annular portion and a spring, or formed as a cutout or a hole so as not to partition the valve- You just need to install a passage. Since this passage does not need to be provided with a resistance to the fluid passing therethrough, it is possible to form a hole or notch in the plate spring 4 freely. Further, since the shape of the passage has a degree of freedom, the degree of freedom in designing the bending rigidity is increased, and the fatigue endurance due to the repeated bending is also easily secured.

In the case of the present embodiment, the pilot valve (PV) is provided with a pilot valve seat member (21) and a pilot valve body (22). The pilot valve seat member 21 includes a valve accommodating cylinder 21a formed in a cylindrical shape and having a through hole 21c communicating with the inside and the outside of the valve accommodating cylinder 21a and an annular pilot valve seat 21d. The pilot valve body 22 has a small diameter portion 22a slidably inserted in the valve receiving cylinder 21a, a large diameter portion 22b formed to have a large diameter in comparison with the small diameter portion 22a, And a concave portion 22c formed between the large diameter portion 22a and the large diameter portion 22b and opposed to the through hole 21c. In the pilot valve (PV), the end portion of the large diameter portion (22b) of the pilot valve body (22) is seated on the pilot valve seat (21d). The pilot valve PV can reduce the pressure receiving area A where the pressure acts in the direction in which the pilot valve element 22 is pulled out from the pilot valve seat member 21 as shown in Fig. Then, the hydraulic pressure area A can be reduced and the flow passage area at the time of valve opening can be increased.

Here, the case where the pilot valve PV is a poppet valve that simply opens and closes the port is compared as a comparative example. In this comparative example, inertia also acts. Therefore, the distance by which the valve body of the pilot valve is separated from the valve seat dynamically depends on the thrust of the solenoid, the biasing force of the coil spring for biasing the valve body, and the biasing force The two forces are converged at a position that is statically balanced rather than a position that is statically balanced, after being overshooted and displaced beyond a position that is statically balanced by vibration. The pilot valve of the comparative example has a small flow passage area with respect to the valve opening amount of the pilot valve. As a result, the amount of separation of the pilot valve from the valve seat tends to increase. Therefore, as shown by the broken line in Fig. 5, after the pilot valve is opened, a long time is required until the valve element is stabilized at a position where it is statically balanced (a position indicated by a dot-dashed line in Fig. 5). Further, since the overshoot is conspicuous, the generated damping force suddenly changes, and it takes time until the damping force is stabilized.

In order to solve this problem, the amount of the flow path area can be increased with respect to the valve opening amount of the pilot valve. However, in this case, since the pilot valve in the comparative example is a poppet valve, the diameter of the annular valve seat on which the poppet valve is seated is required to be large. As a result, the pressure receiving area where the pressure acts in the direction of separating the poppet valve from the annular valve seat becomes large. Therefore, since the solenoid must output a large thrust, there is a fear that the damping valve becomes large.

On the other hand, in the pilot valve (PV) of the present embodiment, the pressure receiving area for receiving the pressure for separating the pilot valve body (22) from the pilot valve seat (21d) The flow path area with respect to the separation distance from the sheet 21d can be increased. As a result, as shown by the solid line in FIG. 5, the convergence time to the static balance position of the pilot valve element 22 can be shortened without causing the solenoid (Sol) to increase in size. Therefore, sudden changes in the damping force can be suppressed without causing the damping valve V to be large-sized. Therefore, it is possible to exhibit stable damping force with good response.

In the damping valve V, the thrust corresponding to the current supplied to the solenoid (Sol) is applied to the pilot valve (PV) to control the internal pressure of the back pressure chamber (P) The valve opening pressure in the valve body 3 is adjusted. Thereby, the internal pressure of the back pressure chamber P can be adjusted as desired without depending on the flow rate flowing through the pilot passage 23. [ Therefore, even when the piston speed of the shock absorber D is low, the damping force change with respect to the supply current to the solenoid (Sol) is close to linear, so that the controllability can be improved. Since the internal pressure of the back pressure chamber P for pressing the sub valve body 3 is controlled by applying the thrust corresponding to the supply current to the solenoid (Sol) to the pilot valve (PV), the fluctuation of the damping force can be reduced have.

At the time of failure, supply of current to the solenoid (Sol) is cut off, and the pilot valve body (22) is urged by the coil spring (33). Thereby, the opening end on the opposite side of the valve housing 20 of the fail-valve seat member 34 is closed. However, when the pressure in the rod chamber 13 reaches the valve opening pressure, the fail valve F opens and the pilot passage 23 communicates with the reservoir 17. Thus, the fail valve F serves as a resistance against the flow of the hydraulic oil, and the shock absorber D functions as a passive shock absorber. The damping characteristic with respect to the piston speed of the shock absorber D at the time of failure can be arbitrarily set in advance by setting the valve opening pressure of the fail valve F. [

In the present embodiment, the pressure of the back pressure chamber P is controlled by the solenoid (Sol) to control the valve opening pressure of the main valve body 2 and the sub valve body 3. However, even when the pressure of the back pressure chamber P is not controlled using the pilot valve PV as a passive pressure control valve without controlling the valve opening pressure of the pilot valve PV by the solenoid (Sol) It is possible to make the pressure increasing ratio of the main body 3 smaller than the pressure increasing ratio of the main valve body 2. [ Therefore, the attenuation characteristic can be changed in two steps. Therefore, when the piston speed is in the low speed region, a soft damping force can be outputted, and the damping force is not increased. Further, it is possible to output the hard damping force required when the piston speed is in the high speed region, and the damping force shortage can be solved.

The main valve body 2 is laminated on the valve seat member 1 in a floating state. As a result, the port 1a can be largely opened, and the damping coefficient at the time of valve opening of the main valve body 2 can be reduced. Therefore, it is very easy to control the damping force by the solenoid (Sol).

The diaphragm spring 4 urges the main valve body 2 to promote the return to the seating position on the first valve seat 1b after the main valve body 2 opens the port 1a . Therefore, the closing delay of the port 1a does not occur at the time of switching the expansion / contraction direction of the shock absorber D or the like. Therefore, the damping force generation responsiveness is improved.

In the damping valve V, the first valve seat 1b is formed in an annular shape so that the inner diameter of the second valve seat 2a is set to be larger than the inner diameter of the first valve seat 1b. Therefore, even when the sub valve body 3 is opened, it is possible to reliably create a state in which the main valve body 2 is not opened. Therefore, the attenuation characteristic of the damping valve V can reliably be relieved in two steps. Since the first valve seat 1b and the second valve seat 2a are both annular, the pressure increasing ratio of the main valve body 2 can be easily designed. The first valve seat 1b and the second valve seat 2a are formed in an annular shape to facilitate the design of the pressure increase ratio. However, the present invention is not limited to the annular shape, and may be any shape.

In this embodiment, a back pressure chamber P provided on the opposite side of the main valve seat of the sub valve body 3 is provided, and the sub valve body 3 is pressurized by the pressure in the back pressure chamber P. Therefore, the valve opening pressure of the sub-valve body 3 does not vary from product to product due to the dimensional control of the member forming the back pressure chamber P. Therefore, a stable pressing force can be applied to the sub-valve body 3 and a large pressing force can be applied to the sub-valve body 3.

Further, the pressing means may be composed of only an elastic body such as a dish spring or a coil spring. In this case, in order to vary the pressing force in the pressing means, for example, the initial load given to the elastic body by the actuator may be changed.

And a pilot passage 23 for reducing the pressure on the upstream side of the port 1a and guiding it to the back pressure chamber P. Therefore, the valve opening pressure of the main valve body 2 and the sub valve body 3 can be set using the pressure on the upstream side of the port 1a. And a pilot valve (PV) for controlling the pressure in the back pressure chamber (P). Thereby, the damping force of the damping valve V can be varied by adjusting the valve opening pressure of the main valve body 2 and the sub valve body 3.

In the case of the present embodiment, the pilot passage 23 is provided with an orifice 1f to introduce the pressure of the port 1a into the back pressure chamber P by reducing the pressure. However, in addition to the orifice, the pressure may be reduced by another throttling portion such as choke.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments.

The present application claims priority based on Japanese Patent Application No. 2013-191337 filed on September 17, 2013, the entire contents of which are incorporated herein by reference.

Claims (5)

Damping valve,
A valve seat member having a port and a first valve seat surrounding the port,
A shaft member provided on the valve seat member,
An annular main valve body mounted movably in the axial direction with respect to the shaft member and spaced apart from the first valve seat and having a second valve seat on the opposite side of the valve seat member,
A valve member mounted on the shaft member and spaced apart from the second valve seat,
A valve body gap chamber formed between the main valve body and the sub valve body and formed on the inner peripheral side of the second valve seat,
A restriction passage communicating the port and the valve body chamber to provide resistance to the flow of the passing fluid,
A main valve body pressing means for pressing the main valve body toward the valve seat member side,
And a sub-valve body pressing means for pressing the sub-valve body toward the main valve body,
Wherein the restriction passage is formed by an annular gap between the main valve body and the shaft member. The method according to claim 1,
The main valve body pressing means is a plate spring fixed to the shaft member,
Wherein the main valve body has a protrusion that is fitted with an interval between the outer circumference of the diaphragm spring and a position in the radial direction is defined by the diaphragm spring. The method according to claim 1,
Wherein the first valve seat and the second valve seat are provided in an annular shape,
Wherein an inner diameter of the second valve seat is larger than an inner diameter of the first valve seat. The method according to claim 1,
The sub-valve body pressing means has a back pressure chamber on the side opposite to the main valve body in the sub-valve body,
And the sub-valve body is pressurized by the pressure in the back-pressure chamber. 5. The method of claim 4,
Wherein the back pressure chamber is provided with a pilot passage through which the pressure on the upstream side of the port is reduced.

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